Sequential SNAr and Diels–Alder reactivity of superelectrophilic 10π heteroaromatic substrates

Synthesis, crystal structure elucidation, DFT analysis, drug‐likeness and ADMET evaluation and molecular docking studies of triazole derivatives: Binary inhibition of spike protein and ACE2 receptor protein of COVID ‐19

The recent incidence of terrible acute respiratory syndrome coronavirus 2 (SARS CoV‐2) has presently experienced some noteworthy mutations since its discovery in 2019 in Wuhan, China. The present research work focuses on the synthesis of three triazole derivatives (BMTPP, BMTTP, and BMTIP) and their inhibition activities against SARS‐Cov‐2 spike and ACE2 receptor proteins. The crystal structure for BMTTP was determined by the SCXRD method and optimized geometrical parameters for the three triazole derivatives were obtained by DFT calculations. HOMO‐LUMO, Global reactive descriptors [GRD], and Molecular electrostatic potential (MEP) investigations exposed that all three compounds have biological properties. The drug‐likeness ability of the synthesized compounds was examined using Molinspiration and a pre‐ADMET online Server. Further, to explore the binding nature of three synthesized compounds with SARS‐Cov‐2 spike proteins/ACE2 receptor molecular docking studies were executed. The outcomes we obtained from molecular docking simulation studies suggest that the synthesized triazole derivatives may be well utilized as curing medicines against COVID‐19. Ultimately, animal tests and precise clinical tests are required to prove the potent nature of these compounds against COVID‐19. Finally, the present outcomes must be proved to utilize in‐vitro and in‐vivo antiviral methods.

Mechanisms of nitric oxide generation in living systems

In modern chemical and biochemical studies, special attention is paid to molecular systems capable of generating nitric oxide (NO), which is one of the most important signalling molecules in the body and can trigger a whole cascade of reactions. Despite the importance of this molecule, the mechanisms of its formation in living organisms remain a subject of debate. This review combines the most important methods of releasing NO from endogenous and exogenous sources. The history of endogenous NO donors dates back more than 150 years, since the synthesis of nitroglycerin, which remains the standard vasodilator today, even though it is known that it and many other similar compounds lead to the development of a nitrate tolerance. Particular awareness is devoted to the mechanisms of NO formation without the participation of enzymes, since these methods are most important for creating exogenous sources of NO as drugs. The study of NO formation methods is centred on both the creation of new NO donors and understanding the mechanisms of tolerance to them.

Highly conjugated architectures and labile reaction intermediates from coupling between 10π electron-deficient heteroaromatics andsym-trihydroxy- or triamino-benzene derivatives

The C–C coupling reaction between neutral aromatic carbon nucleophiles such as 1,3,5-triamino- and 1,3,5-trihydroxy-benzene derivatives and 7-chloro-4,6-dinitrobenzofuroxan (Cl-DNBF) or 7-chloro-4,6-dinitrobenzofurazan (Cl-DNBZ) gave in high yield the corresponding conjugated structures, which are of potential interest in the materials field. When chlorine is absent on the electrophile, as in 4,6-dinitrobenzofurazan (DNBZ), the reaction with 1,3,5-triaminobenzene derivatives produces Wheland–Meisenheimer (WM) zwitterionic intermediates, intercepted and fully characterized via NMR at low temperature, whereas stable Meisenheimer complexes (M) were isolated in the reaction of phloroglucinol with 1,3,5-trimethoxybenzene. The latter also gave exclusively M complexes when reacted with 4,6-dinitrobenzofuroxan (DNBF), or 4,6-dinitrotetrazolopyridine (DNTP). The detection of WM or M intermediates can be rationalized by invoking the substituent stabilization ability of the positive charge in WM intermediates, on going from neutral carbon nucleophiles 1,3,5-triaminobenzenes to 1,3,5-trihydroxybenzene derivatives. Furthermore, variable-temperature NMR experiments on the M intermediates gave insights into the rotational barrier about the newly formed C–C bond.

Novel intermediates of the S_EAr/S_NAr reaction (WM or M complexes) have been detected and characterized by NMR at low temperature.

Applications of the Conceptual Density Functional Theory Indices to Organic Chemistry Reactivity

Theoretical reactivity indices based on the conceptual Density Functional Theory (DFT) have become a powerful tool for the semiquantitative study of organic reactivity. A large number of reactivity indices have been proposed in the literature. Herein, global quantities like the electronic chemical potential μ, the electrophilicity ω and the nucleophilicity N indices, and local condensed indices like the electrophilic P k + and nucleophilic P k - Parr functions, as the most relevant indices for the study of organic reactivity, are discussed.